In the process of ultrasonically soldering aluminum tube joints that are a part of an assembly the joints including adjacent portions of the assembly are immersed in a pot of molten solder while being exposed to ultrasonic energy generated by a plurality of transducers spaced on the outer surface of the pot.
The cavitation caused by the ultrasonic energy is effective in breaking and removing the oxide coating from the aluminum surface in the joint area so that the solder adheres to the aluminum surfaces and forms a seal. The location of the joint area relative to the level of the solder is carefully selected so as to effectively remove the oxide without causing damage to the tubing.
Generally the areas of the molten solder that are closer to the transducers or source of energy are subjected to higher energy and greater cavitation.
In many instances such as in soldering joints wherein the joint is part of an assembly, other parts of the assembly may be located by necessity closer to the energy source. When so located, they are, as a result, subjected to greater cavitation of the solder than the joint area. In some instances, the cavitation of the solder may be great enough to cause sufficient surface erosion to weaken the tubing and cause rupturing of the tubes under certain pressure conditions.